I already have an existing Laravel Spark site running that employs the Stripe payment provider. I noticed that the newest Laravel Spark supports PayPal using the Paddle payment provider. On the spark website, it says:
Supported Payment Providers
Spark supports two payment providers, and purchasing a Spark license grants you the ability to use either of these payment providers.
I guess it's therefore not possible to combine both providers and have a single site that allows users to use Stripe or Paddle?
Out of the box it's not possible to use both payment providers. Once a provider is selected during the installation of Spark, you'll end up with either the laravel/spark-paddle composer package or the laravel/spark-stripe package.
It's probably possible to hack Spark to support both providers, but there will be a bunch of conflicts to work around. For example, the two packages will have conflicting migrations.
It would be much easier to create a custom solution.